The aim of this project is to construct a two-photon confocal microscope with optical ablation and trapping capabilities. The ability to non-invasively monitor cellular systems before and after optical manipulation is crucial. This project will proceed in two stages. First, a two-photon microscope will be construct in LAMMP, then laser tweezers and scissors will be implemented in the new microscope. We are now working toward the completion the first stage. We have purchased a Titanium-Sapphire laser. This is the most important element in the two-photon system because the high peak power femtosecond laser ensures efficient two-photon excitation. We are also in the process of evaluating the effect of two-photon micro-irradiation on biological system. Significant progress has been made in the characterization of two-photon irradiation damage using Chinese hamster ovary (CHO) cells. We found that two-photon irradiation above a threshold dosage can cause auto-fluorescence increase in CHO cell indicating cellular damage. The observed auto-fluorescence increase is providing valuable clues in understanding the mechanism of two-photon damage and will be further studied in the near future.